This has been studied a lot and there’s really no evidence that holding the ball this way improves velocity. I played fast pitch softball for 8 years and had to quit as a sophomore and still received a couple D1 college offers. I do think finding a seam in any fashion helps with grip and therefore accuracy, but velocity comes down to form and strength. A good wrist snap helps a ton.
This controls any run you'll get on the throw. I'm a lefty and play slowpitch. If I grip a 2 seam when I throw, it'll run 3 feet to the left when I throw from first to home. 4 seam grip has no run
